Tetrahydrofuran → Ethyl 2-(diphenylmethyleneamino)-6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)hexanoate

HRID 579487Notes

Reaction equation

HRID 579487 reaction equation
[CH2:1]([O:3][C:4](=[O:20])[CH2:5][N:6]=[C:7]([C:14]1[CH:19]=[CH:18][CH:17]=[CH:16][CH:15]=1)[C:8]1[CH:13]=[CH:12][CH:11]=[CH:10][CH:9]=1)[CH3:2].Br[CH2:22][CH2:23][CH2:24][CH2:25][B:26]1[O:30][C:29]([CH3:32])([CH3:31])[C:28]([CH3:34])([CH3:33])[O:27]1.C1COCC1.C[Si]([N-][Si](C)(C)C)(C)C.[Li+]>C(OCC)(=O)C>[C:8]1([C:7](=[N:6][CH:5]([CH2:22][CH2:23][CH2:24][CH2:25][B:26]2[O:30][C:29]([CH3:32])([CH3:31])[C:28]([CH3:33])([CH3:34])[O:27]2)[C:4]([O:3][CH2:1][CH3:2])=[O:20])[C:14]2[CH:19]=[CH:18][CH:17]=[CH:16][CH:15]=2)[CH:9]=[CH:10][CH:11]=[CH:12][CH:13]=1

Participants

6

Reactant 4

HCID 8028TetrahydrofuranHCID 319508Ethyl 2-(diphenylmethyleneamino)acetateHCID 2733832Lithium HexamethyldisilazideHCID 111963112-(4-Bromobutyl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane

Product 1

HCID 86663712Ethyl 2-(diphenylmethyleneamino)-6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)hexanoateYield 64.3%

Reagents, catalysts & solvents 1

HCID 8857Ethyl AcetateSolvent

Conditions

Temperature
50 °C

Procedure

A solution of N-(diphenylmethylene)glycine ethyl ester (8.24 g, 30.8 mmol) and 2-(4-bromobutyl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (8.92 g, 33.9 mmol) in freshly distilled THF (77 mL, 0.4 M) was cooled to −78° C. and treated with lithium bis(trimethylsilyl)amide (32.3 mL, 1.0 M in THF). Once the addition was complete, the reaction was warmed to 50° C. and heated for 8 h. After being complete by TLC, the reaction mixture was cooled to 0° C., diluted with ethyl acetate and washed successively with saturated aqueous NaHCO3 and saturated aqueous NaCl, dried over MgSO4, filtered and concentrated. Rapid purification by MPLC (1-15% ethyl acetate in heptane with 0.5% triethylamine over 6 CV) gave ethyl 2-(diphenylmethyleneamino)-6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)hexanoate as a colorless oil (8.9 g, 64%). Rf 0.40 (30% ethyl acetate in heptane).

Workup

  1. additionOnce the addition
  2. temperatureheated for 8 h
  3. temperaturethe reaction mixture was cooled to 0° C.
  4. washwashed successively with saturated aqueous NaHCO3 and saturated aqueous NaCl
  5. dry with materialdried over MgSO4
  6. filtrationfiltered
  7. concentrationconcentrated
  8. customRapid purification by MPLC (1-15% ethyl acetate in heptane with 0.5% triethylamine over 6 CV)

Sources & evidence

ORD record
ord-9e22f3b5fdda46a881985e80fd92647c
Source dataset
uspto-grants-2015_05
Patent number
US09040703B2

Reaction notes

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